Apparatus for aiding hearing



Aug. 7, 1928. 1,679,532

F. W. KRANZ APPARATUS FOR AIDING HEARING Fiied Oct. 10. 1921 4 illl -lll} 2 10 l l i lll A Q I Patented Aug, 7, 1928.

UNITED STATES I I FREDERICK WILLIAM KRANZ, OF GENEVA, ILLINOIS.

.AIEZ EfALRALI.US FOR AIDING' HEARING.-

Application filed October 10, 1921. Serial No. 506,640.

This invention relates to apparatus for helping persons hard of hearing or those commonly referred to as deaf to hear various sounds, and it has been-my purpose to provide an improved apparatus of this type. More specifically,- my invention is an improvement upon that disclosed in Patent No. 1343,717, granted January 15, 1920, to E. C. Hanson. Whereas, in the Hanson inven- 'tion, the object was to increase the volume of speech producedin the receiver, in my invention the purpose is toimprove the speech quality in comparison with usual devices and yet maintain suificient volume for the purpose for which it is to be used. My device is of the telephonic type, making use of. a transmitter, an amplifier and a receiver,

and the improvement in speech quality is accomplished by the transmission and reproduction. ofall the speech frequencies with comparably the same efficiency, except as an accentuation or suppression of some frequencies is desirable because of the characteristics of the listeners ear or be cause of disturbing noises, this to be accomplished by control of the efficiencies of the transmitter, the amplifier and the receiver as a function of frequency.

In the annexed drawing, there is disclosed diagrammatically, in Fig.1, a system of wiring preferably used, in an apparatus according to my invention, and, in Fig. 2, a modification thereof, numeral 1 designating the transmitter, 2 theamplifier and 3 the receiver, The transmitter 1 and the-amplifier 2 are connected by a transformer, 4, while amplifier2- and receiver 3 are connected by a transformer 5. Within the amplifier there is preferably another transformer 6 and a pair of vacuum tubes 7 and 8, there being connected in the circuits of this apparatus suitable sources of potential 9, 10 and 11, as is well understood in this'art.

My improvement consists primarily in the use of a transmitter and a receiver having chosen natural frequencies, and secondarily of inserting in the amplifier suitable induct-ance, capacity and resistance elements. With a carbon ball'transmitter the higher speech frequencies are inefliciently reproduced and I, therefore, make use of a dia-' phragm as; illustrated- "diagrammatically at 12 with a transmitter button of granularcarrange of vibration.

usual speech frequencies. It 'is considered preferable to have a difference of at least 500 periods per second between the natural tion rates is considered sufficient in cases where one of the instruments has a natural period of 500 periods per second or less.

The foregoing relates to the control of'the frequency characteristics of the transmitter and receiver, while the following relates'to the control of the frequency characteristics of the amplifier. This latter'would be accomplished by the introduction of-a suitable combination of resistance, inductance and. ca-

pacity in the electrical circuit of the amplifier. In Fig. 2, numeral 13 designates the resistance, 14 the capacity and 15 the inductance. These may be connected either in series, in shunt, or both.- This would bea poss ble arrangement for the elimination of the distortional effect of the diaphragms on the speech, or could be used-to accentuate relatively those frequencies for'which the listener is mostdea Users of existing apparatus findthat suchapparatus has a tendency to increase the volume of sound, accentuating primarily those frequencies corresponding to the natural period of the vibrating member of the transmltter. It is the purpose of my apparatus to accentuate to a certain degree such sounds but not to the extent of producing a mere noise. The purpose of selecting, transmitters andf-g-recelvers having 'natural' periods differing by a considerableamount is distribute the sound amplification over a w der range of periodicities, and consequently a wider range of pitch. 'Another purpose of this selection of the periodicities of the transmitter and receiver is in order to avoid double a plification of a limited It is, of course, understood that thespeci- 'bon. The natural vibration periods of thisyfic description ofstructure and methods set and the receiver should be Well separated, especially-if they are -Witlllll the limits of forth above may be departed from without departing from'the splritof my invention f as set forth in this specification and the appended claims.

Having now described my invention, I claim:

1. In a method for aiding hearing, comprising accentuating the frequencies to which the person hard of hearing is less sensitive.

2. In a method for aiding hearing, comprising modifying the intensity of the frequencies in an audible range of frequencies whereby the frequencies which are less impressionable to the ears of a person hard of hearing will be proportionately augmented to effect the hearing of the person as of normal.

In a method for aiding hearing, comprising accentuating the tone frequencies of an audible range of frequencies to which a person hard of hearing is dcl'cctively sensitive in the ratio of the deficiency of sensitivity of the person.

4. In an apparatus for aiding hearing, a receiver, a transmitter, and an amplifier including means for modifying the intensities of the frequencies being transmitted in accordance with the sensitivity defectivene.-.;s in speech frequencies in one hard of hearing whereby the received frequencies are accentuated proportionately.

5. In an apparatus for aiding hearing, a receiver, a transmitter, and an amplifier, the transmitter having means for controlling the relative intensities characteristic of the transmitted frequencies in proportion to the defective sensitivity of the person hard of hearing.

6. In an'apparatus for aiding hearing, a sound transmitter and a sound receiver whose natural periods differ by an interval of an octave or more.

7. In an apparatus for aiding hearing, a

hard of hearing, comprising a transmitter, a receiver, an amplifier, and means cooperating with said amplifier and. said transmitter and receiver for cll'ecting certain frequencies whereby the frequencies to which the person is less sensitive will be impressed upon the ear with equal ell'cct with those to which the person is more sensitive.

9. In an apparatus for aiding hearing, a soundtransmitter and a sound receiver whose natural periods differ by 500 or more vibrations per second.

10. In an appa 'atus for aiding hearing, a sound transmitter and a sound receiver whose natural periods differ by 500 or more vibrations per second, and by an interval of an'octave or more.

11. A telephone receiver, a telephone transmitter, an electric circuit between the receiver and transmitter, and means in the circuit to distort normal tones to neutralize the distortion of the patients ear for such tones.

12. A telephone receiver, a telephone transmitter, anelectric circuit between the two, and means in the circuit to distort certain selected tones by amplification, and other selected tones by reduction to neutralize the distortion of such tones present in the patients ear. I

13. A telephone receiver, a telephone transmitter, an electric circuit between the two, and means in the circuit to distort certain selected tones to neutralize the distortion of said tones present in the patients car.

1 1. A telephone receiver, a. telephone transmitter, an electric circuit between the two, and means to change certain selected tones in the circuit to make them audible to a patients ear in which the unchanged tones are not audible.

15. In a device of the character described, a telephone circuit and means therein to change certain tones inaudible to a patients car by an amount necessary to make them audible to said ear.

In witness whereof, I hereunto subscribe my name to this specification. I

FREDERICK W. KRANZ. 

